## Autos: jacking capacity

Self-tutoring about autos: the tutor looks into the capacity one might need for a vehicle jack. One of the vehicles I maintain, I was surprised to learn, has a curb weight of around 4500 pounds. Yet it seems to me …

## Autos: battery test

Self-tutoring about car maintenance: the tutor mentions a resource. I was checking over a car then thought about the battery. I decided to refresh my memory about how to check it. What I seemed to pick up is that 12.5V …

## Computer science: compile-time errors vs logic errors

Self-tutoring about computer science: the tutor mentions some ideas about programming errors. Writing programs in computer languages, some common types of errors are compile-time errors and logic errors. A compile-time error is one that the compiler has noticed. In simple …

## Exams, retrospect: windfalls, part 2

Self-tutoring about exams and events from the past: the tutor continues from last post. Continuing from my previous post, the idea is that a teacher generously, yet surprisingly, allowed a student to give out a hint to the class during …

## Exams, retrospect: windfalls, part 1

Self-tutoring about exams and events about them: the tutor gives a curious recollection. When I was a kid, during a spelling test (grade 4), the teacher called out “Chicago,” which was on the word list that week. I was new …

## Exponents and logs: a decay equation from a half life.

Tutoring math, you see exponential growth and decay. The tutor mentions an equation from a half life. Example: a specimen loses half activity every 45 days. Find a equation for it. Answer: The equation will be of the form P …

## Retrospect: left and right

Self-tutoring about primary lessons: the tutor mentions his realization of the directions of left and right. When I was a kid, I heard adults refer to left and/or right often. While I knew they were positions or directions of some …

## Geography: latitude: NC and Algiers, Algeria

Self-tutoring about relative latitude: the tutor makes an observation. Lately I’ve been watching “Outer Banks”, set on coastal North Carolina. The setting looks tropical, with palm trees, live oaks (I assume), etc. I once read that if you draw a …

## Music, frequencies and octaves, part 1

Self-tutoring about musical frequencies: the tutor mentions an example. I recall, from back when I was a kid, someone suggesting that an octave above means doubling the frequency. I decided to check: apparently it’s true. For example, middle C has …

## Electronics: inverter vs rectifier

Tutoring applied physics, terms from electronics might arise. The tutor mentions two related ones. An inverter, when relating to power supply, takes DC power and converts it to AC. A rectifier does the opposite. Source: exro.com arrow.com